What little information I can find, indicates that Blackboard is self-hostable, and that the "hosted" option they provide is actually an extra service.
The argument is against a solution that has no possibility for self-hosting and maintaining control of data. That they offer a hosted/SaaS option is irrelevant, because they also offer a regular self-hosted solution.
The argument is against a solution that has no possibility for self-hosting and maintaining control of data. That they offer a hosted/SaaS option is irrelevant, because they also offer a regular self-hosted solution.